A STUDY OF MENTAL ACTIVITY AMONG HEALTHY MEDICAL STUDENTS USING A VIRTUAL MODEL TO INVESTIGATE ACUTE COGNITIVE STRESS EFFECTS

Studies have shown that first-year medical students, experience psychological stress and, in some cases, mental illness due to new environments and stressful study regimes of the medical universities. An experimental study was conducted on first and next (2-3) year medical students of both genders. In the acute stress-recognized virtual model, participants were exposed to two increasing complexity visual tasks. Some derivative indices: correct answers in percent (CA%), reaction sustainability (RS), and functional ability level (FAL) were calculated based on the reaction time measures during simple and complex sensorimotor reactions (SSMRT, CSMRT). For statistical analysis ANOVA and Bonferroni correction t-test was used. No significant differences were found in mental activity between the two genders in 2-3 year medical students, except for CA% in the males' group during CSMRT which indicates that males concentrate well; There were significant differences in parameters of SSMRT (RS; CA%) and CSMRT (RS; FAL; CA%) between first-year males and females; Significant differences were found also in parameters of SSMRT (RS; CA%) and CSMRT (FAL; CA%) between first and next-year medical students in the females' group and no significant differences between first and next-year medical students in males group. Seems independent of gender, in 2-3 year medical students the sensorimotor and cognitive abilities are almost the same. The better mental performance parameters in the male group of first-year students can be explained only by the presence of certain stress in the female group, which can be related to the difficulty adapting to new environments and stressful learning regimes. In addition, male students are able to concentrate better compared to females on acute visual stress. Our results contribute to a better understanding of the psychophysiology of mental activity and further demonstrate how a virtual model can be used to investigate acute cognitive stress effects.  Article visualizations

On Modeling of Synthesis Process of Boron Carbide Based Nanocomposites

Nanocomposites based on boron carbide B4C are hard materials with wide field of applications in modern technologies. A system of first-order ordinary differential equations that simulates the process of chemical synthesis of nanopowders of B4C–TiB2 compositions containing titanium diboride (TiB2) as an additional phase is suggested and resolved numerically for a typical ratio of reaction constants. Reagents and products concentrations are found as time-functions. In this way, the optimal route of production technology of boron carbide-based nanomaterials can be identified

On Modeling of Synthesis Process of Boron Carbide Based Nanocomposites

Nanocomposites based on boron carbide B4C are hard materials with wide field of applications in modern technologies. A system of first-order ordinary differential equations that simulates the process of chemical synthesis of nanopowders of B4C–TiB2 compositions containing titanium diboride (TiB2) as an additional phase is suggested and resolved numerically for a typical ratio of reaction constants. Reagents and products concentrations are found as time-functions. In this way, the optimal route of production technology of boron carbide-based nanomaterials can be identified

Advanced Boron Carbide Matrix Nanocomposites Obtained from Liquid-Charge: Focused Review

Boron carbide is known as a hard material; it possesses a unique complex of physical-mechanical properties and has diverse applications in industries. An expansion of its field of uses stems from the creation of boron carbide matrix nanocomposite materials. In view of this perspective, an effective liquid-charge synthesizing method for their components in nanopowder form has been proposed. This paper provides a focused review on advanced boron carbide matrix ceramic and metal-ceramic nanocomposites recently obtained by the authors using this method. Particular attention is paid to the characterization of boron carbide nanocomposites, including some ceramic borides, metallic alloys and also other metal-ceramic composites